User login, password always wrong

[DarkCorner]

I created a new user that I put in the "admin" group, but on login it keeps telling me that the username or password is incorrect.
Of course I tried to change the password.
The username is 10 characters, but I don't think that's the problem because in other Debian servers I can use it.

 

[anodos]

I created a new user that I put in the "admin" group, but on login it keeps telling me that the username or password is incorrect.
Of course I tried to change the password.
The username is 10 characters, but I don't think that's the problem because in other Debian servers I can use it.

Validation is for auxiliary group `builtin_administrators`